US President 'seeking nuclear war' with new policy: NKorean institute

US President Donald Trump is "seeking nuclear war" through a controversial new push to revamp Americas nuclear arsenal, an institute attached to North Koreas foreign ministry said Tuesday.

The Pentagon's so-called Nuclear Posture Review, unveiled last week, outlined plans to develop new low-yield atomic weapons -- a move it said was necessary to confront a worsening security climate and in response to actions taken by Russia and China.

The review marked the first time since 2010 that the US military has spelled out how it foresees nuclear threats in the coming decades, and has triggered accusations that Trump's administration is seeking to lower the threshold for a nuclear strike.

Moscow has slammed the policy as "bellicose" and "anti-Russian" while China has called Washington's assessments of its nuclear intentions "wild guesses" and Iran accused the United States of bringing the world "closer to annihilation".

North Korea's state news agency KCNA on Tuesday reported an official as saying the US had "made a declaration of war against the whole world".

"This clearly shows that Trump is seeking nuclear war," a spokesman for the Institute for American Studies, a research and advisory agency under the North's foreign ministry, was quoted as saying.

"The US is becoming all the more undisguised in its attempt to maintain its sphere of world domination by wantonly violating the international law, clinging to highhandedness and arbitrariness, and wildly brandishing its nuclear club."

The spokesman said it proved that "we were absolutely right in having bolstered up the nuclear deterrent", referring to the North's recent attempts to boost its own atomic weapons programme in defiance of international condemnation.

He added that it further hardened the North's determination to "resolutely continue the road we chose".

However, he also maintained that "as a peace-loving and responsible nuclear power" the North would not use nuclear weapons unless aggressive hostile forces infringe upon our sovereignty and interest".

Tensions between Washington and Pyongyang have soared in the past year as the North launched a series of missiles and staged its most powerful nuclear test to date.

North Korean leader Kim Jong-Un declared his country a fully-fledged nuclear power in November after testing an intercontinental ballistic missile the regime claimed was capable of reaching the US mainland.

Trump has meanwhile derided Kim as "little rocket man" and threatened to "utterly destroy" the regime in the event of an attack.